I've been using this light for a few weeks now. Definitely the brightest light I've used to date. It has a sufficient number of modes (2 flashing, solid and group ride). The mounts are decent quality, it comes with two, a seatpost and a seatstay mount. I've been using the seatstay mount so far. The first ride, I noticed it was pointing at the ground after only 15 minutes. I moved it back up and tightened the thumb screw a bit, 15 minutes after it was aiming down again. I had to make the thumb screw literally as tight as I could with my fingers to get it to stay, and even at that it went down 1 notch in the last hour of my ride. I may try to find a Philips screw to replace it so I can tighten it a little more with a screwdriver. That's really the only down side, otherwise it's an excellent light.

I can't imagine ever needing a rear light that is brighter than this one.

Compared to the Planet Bike Blinky 5 & Blinky 7 which I previously thought were pretty bright...This thing is a supernova! It can be mounted on either the seat stay or seat post. It has a thumbscrew making it a tool-less installation. There is only one clip that mounts to the light so you can't put one of each mount on different bikes.

I ended up tie-wrapping mine to the back of my helmet because I ride several bikes after dark and didn't want to switch mounts around.

Oddly enough it came with zero instructions. Not that it's rocket science but nothing is a little weird. Time to full charge and whether it has any low battery indication remain a mystery. I can tell you that it glows a dim red while charging and then turns to blue when it is fully charged.